Polyurethane foam preparation using siloxane glycol branch copolymers



United States Patent 9 3 398,104 POLYURETHANE FdAM PREPARATION USINGSILOXANE GLYCOL BRANCH COPOLYMERS Loren A. Haluska, Midland, Micl1.,assignor to Dow Corning Corporation, Midland, MlClL, a corporation ofMichigan No Drawing. Continuation-impart of application Ser. No.127,843, July 31, 1961. This application July 16, 1965, Ser. No. 472,721

18 Claims. (Cl. 2602.5)

ABSTRACT OF THE DISCLOSURE The preparation of polyurethane foams withnovel siloxane glycol copolymers is disclosed. The use of thesecopolymers allows greater processing latitude than was possibleheretofore and results in foams which do not exhibit the undesirablepneumatic effect.

This application is a continuation-in-part of application Ser. No.127,843, filed July 31, 1961, and nOW abandoned.

This invention relates to the use of certain block copolymers ofpolysiloxanes and polyalkylene oxides, in which the blocks of polymerare tied together through silicon carbon bonds, in the preparation ofpolyurethane foams.

It is known that certain copolymers of alkylene oxides and polysiloxanesin which the siloxane blocks and the alkylene oxide blocks are tiedtogether through SiOC linkages are useful as surfactants in the controlof polyurethane foams. It is also known that certain linear copolymersof alkylene oxides and polysiloxanes in which the polymer blocks aretied together through silicon carbon bonds are useful as surfactants inthe control of polyurethane foams. The latter materials have a distinctadvantage over the former since they are non-hydrolyzable and hence arestable to deterioration by water or other materials containing reactivehydroxyls. This means that the latter type of surfactant can be storedunder moist conditions or stored admixed with the polyethers prior tofoaming.

However, the polyoxyalkylene polysiloxane copolymers which are tiedtogether through silicon carbon bonds which have heretofore been known,suffered from the disadvantage that the one-shot flexible foams formedemploying them as surfactants exhibited a so-called pneumatic effect.That is when the foam was compressed and the pressure released the foamdid not immediately return to its original shape. This is verydisadvantageous when the foam is to be used as a cushion. Although thepneumatic effect can be eliminated by mechanically crushing the foam soas to rupture the closed cells, this operation represents an added stepin the production of polyurethane foams and hence is undesirable from acost standpoint.

It is the primary object of this invention to provide novel copolymerswhich are useful as surfactants and as emulsifying agents. Anotherobject is to provide a stable nonhydrolyza ble surfactant forpolyurethane foams which does not give a pneumatic eifect in the foam. A

3,398,104 Patented Aug. 20, 1968 further object is to provide superiorsurfactants for the production of polyurethane foams which exhibitexcellent solubility in water and excellent stability in mixtures withpolyglycols, amines and fluorocarbons. A still further object is toprovide surfactants for the production of polyurethane foams which allowgreater processing latitude in that they permit broader formulaedeviation-s, wider catalyst tolerances and they help to produce a goodfoam over a wider physical range of manufacturing conditions. Otherobjects and advantages will be apparent from the following description.

This invention relates to the prepartion of polyurethane foams employingcopolymers having the average structural formulae of the group (1)R,,Si[ (OSiMe (OSiMeG) OSiMe G] (2) GMe Si(OSiMe (OSiMeG) OSiMe G (3) MeSi(OSiMe (OSiMeG) OSiMe (4) R,,Si[(OSiMe (OSiMeG) ,OSiMe in whichformulae R is a hydrocarbon radical free of aliphatic unsaturation andcontains from 1 to 10 carbon atoms, Me is a methyl radical, G is aradical of the structure D(OR") A wherein D is an alkylene radical, R"is composed of ethylene radicals and radicals selected from the groupconsisting of propylene and butylene radicals, the amount of ethyleneradicals relative to the other alkylene radicals being such that theratio of carbon atoms to oxygen atoms in the total OR" blocks rangesfrom 2.3 :1 to 2.8: 1, in has an average value from 25 to 100, A is aradical selected from the group consisting of the OR, OO-CR' andradicals wherein R is a radical free of aliphatic unsaturation selectedfrom the group consisting of hydrocarbon and hydrocarbonoxy radicals,the A radical containing a total of less than eleven atoms, a has anaverage value of from 0 to l, n has an average value of from 6 to 420, dhas an average value of from O to 30, b has an average value of from 1to 30, and c has an average value of from 3 to 30, said copolymerscontaining at least 13 percent by weight OSiMe units based on the weightof the co polymer.

It should be understood that the above formulae rep resent the averagemolecular configuration for the products of this invention. In otherwords, the lengths of the dimethylsiloxy blocks and/or the oxyalkyleneblocks in the copolymers are not all the same and can vary con siderablyprovided the average value is such that n and in fall within thespecified ranges. Furthermore, the silicon atoms to which theoxyalkylene blocks are attached need not be evenly spaced along the mainsiloxane chain.

The products of this invention are best made by reacting the omegaalkenyl ether, preferably the allyl ether, of the desired polyalkyleneglycol with the corresponding siloxane containing SiH groups. Thisreaction is best carried out by heating a mixture of the two reactantsin the presence of a platinum catalyst such as platinum dispersed on aninert carrier or a compound of platinum such as chloroplatinic acid, attemperatures from to 200 C. The siloxane reactants can be of fourconfigurations; namely,

(1) V RnSiKOSiMezM(OSiMeHMOSiMmHh-n M83 Me Me;

IIBIG SKO Si) n ()Sl) b SlII (3) Me; H

M038 0 S Si)n O u 0 SiMea and 4 RaSi{(OSii\/lc2)u(0SiMeG)cOSiMeConfiguration (l) is best prepared by cohydrolyzing a silane of theformula R,,SiX with dimethyldichlorosilane, methyldichlorosilane anddimethylmonochlorosilane and thereafter equilibrating the cohydrolyzatewith an acid catalyst such as H 50 The silanes are employed in theproportion of one mol of R SiX n mols of dimethyldichlorosilane, d molsof methyldichlorosilane, and at least 4-a mols ofdimethylmonochlorosilane. Configuration (2) is best prepared bycohydrolyzing the silanes in preparation of n mols: ofdimethyldichlorosilane, two mols of dimethylmonochlorosilane and [1 molsof methyldichlorosilane. The hydrolyzate can then be equilibrated with H50 Configuration (3) is best prepared by cohydrolyzing the silanes inthe proportion of n mols of dimethyldichlorosilane, two mols oftrimethylmonochlorosilane and 0 mols of methyldichlorosilane andthereafter equili-brating the cohydrolyzate as above. Configuration (4)is best prepared by cohydrolyzing one mol of a silane of the formulaR,,SiX with n mols of dimethyldichlorosilane, c mols ofmethyldichlorosilane and at least 4--a mols of trimethylchlorosilane andthereafter equilibrating the cohydrolyzate as above.

For the purpose of this invention, R can be any hydrocarbon radical freeof aliphatic unsaturation of from 1 to carbon atoms such as methyl,ethyl, hexyl, phenyl, tolyl, benzyl, xylyl, methylcyclohexyl,cyclohexyl, cyclopentyl, ,B-phenylpropyl, fl-phenylethyl, decyl andisopropyl.

The omega-alkenylpoly glycol ethers employed in this invention can becopolymers of ethylene oxide and propylene oxide or copolymers ofethylene oxide and butylene oxide or copolymers of all three oxides. Inany event, the proportions of the various alkylene groups should be suchthat the carbon to oxygen ratio in the alkylene glycol ether should befrom 2.3:1 to 2.8:1, preferably from 2.45:1 to 2.55:1. The other ends ofthe .polyalkyleneglycol ether should consist of the group A.

For this purpose of the invention A can be any radical of the formulae-OR', -OOCH or o O OR' in which R can be any hydrocarbon radical free ofaliphatic unsaturation such as methyl, ethyl, butyl, isopropyl,cyclohexyl, phenyl, tolyl, benzyl or zenyl or any hydrocarbonoxy radicalsuch as OCH('CH OMe) In these radicals the total number of C and O atomsif any should not exceed 10, that is, the A radical should contain atotal of less than eleven atoms.

Thus it can be seen that the polyoxyalkylene blocks of the copolymers ofthis invention can be blocked with ether, acyl or carbonate estergroups. These groups are 'best formed by capping thepolyalkyleneglycol-monoomega-alkenyl ether after it is formed by anyconventional procedure. Thus, for example, one may react the alkalimetal salt of the monoallyl ether with an alkyl chloride to produce anOR group or one may react the morroallyl ether with an acyl halide oracide anhydride to produce an OOCR' group or with an alkylchloroformateto produce the O oiion' group. All of these reactions are carried out bywellknown procedures.

The omega alkenyl end of the omega-allrenylpoly glycol ethers can belinear or branched in configuration and can contain any number of carbonatoms, Upon addition of these ethers to, the SiH compound, the alkenylradical becomes an alkylene radical which is represented in the formulaeabove by the symbol D. Specific examples of D are the methylene,ethylene, propylene, isopropylene, butylene, octylene, decylene,octadecylene and myricylene radicals. Preferably D contains from 1 to 18carbon atoms with the propylene radical derived from the allyl etherbeing the most preferred at this time.

The copolymers of this invention are useful in controlling the foamformation in polyurethane resins. The copolymers are operative with anytype of polyurethane polymers such as those based upon polyesters andthose based upon polyethers.

As is well-known, the polyurethane foams are prepared by reacting anorganic isocyanate having at least two isocyanate groups per moleculewith apolyether or polyester resin containing at least two hydroxylgroups per molecule. Preferably the polyesters are reaction products ofaliphatic dihydric o'r polyhydric alcohols and'aliphatic' dicarboxylicacids or hydroxylated monocarboxylic acids. In these materials thehydroxyl groups can appear on the end of the chain by using an excess ofthe alcohol. The hydroxyl groups may also appear along the polyesterchain by employing polyfunctional alcohols such as glycerin,pentaerythritol, trimethylolpropane or trimethylolethane. Also thehydroxyl groups may be in the acidic fragment of the polymer byemploying hydroxylated acids or by employing glycerides or hydroxylatedacids such as castor oil. For the purpose of this invention the basiccomposition of the polyester is not critical nor is the degree ofhydroxylation.

The preferred base polymers are the hydroxylated polyethers which forthe purpose of this invention can be any of those normally employed inthe production of polyurethane polymers. These ethers are particularlydescribed in US. Patent 2,948,691. The composition of the polyether isnot critical for the purpose of this invention, although it is preferredthat the material have a molecular weight of at least 500. In general,the polyethers are reaction products of alkylene oxides such as ethyleneoxide, propylene oxide and butylene oxide with alcohols or water. Thepolyether may also contain some copolymerized polyhydric alcohol such asthose described above.

For the purpose of this invention, any isocyanate having at least twoisocyanate groups per molecule is suitable. These include aliphaticisocyanates such as hexamethylenediisocyanate; cycloaliphaticisocyanates such as cyclohexyl diisocyanate and aromatic isocyanatessuch as naphthalene 1,5-diisocyanate, toluene diisocyanate,4,4'-diphenylmethane diisocyanate,

o l omorcmodstQrrom:

and 4,4-diphenyl diisocy-anate. If desired, the isocyanates can beemployed in molar excess with respect to the OH groups in the polyetherso that excess isocyanate groups provide the gas for foaming theproduct.

Any of the catalysts normally employed in preparing polyurethane foamsare operative in this invention. These include, for example, metalliccompounds such as dibutyltin dilaurate, dibutyltin diacetate or stannousoctoate and amines such as triethylamine, tributylamine andtriethylenediamine. Mixtures of two or more catalysts can be used ifdesired.

The foams of this invention can be prepared employing any blowing agent.In many foams the blowing agent is the evolved CO which results from thereaction of the isocyanate with H 0. However, in other foams it is pref-6 erable to employ volatile fluids such as methylene chloride Theresulting product was a fluid having a viscosity of or thefluorochloromethanes and ethanes generally sold 4,405 cs. and arefractive index of 1.4490. The product under the name Freon. However,the process of this invenhad the average formula tion is not restrictedto these types of agents. In the former EXAMPLE 4 case the water acts asthe blowing agent for the purpose of thisinvenfion' Employing theprocedure of Example 2, 168.5 g. of

The precise amount of the copolymer of this invention needed to producethe optimum foam varies with the pargi f gg g gg was re ticularpolyurethane formulation. However, in general,

satisfactory foams are obtained employing from .1 to 2 percent by weightcopolymer based on the weight of the t total polyurethane foamformulation. If desired, a mixsumsD O iM H ture of two or morecopolymers can be used.

The following examples are illustrative only and should i o not beconstrued as limiting the invention which is propm Xylene at 144 Theefly delineated in the appended damn In the examples had a vrscoslty of1,950 cs. and a refractive index of and claims Me is employed as anabbreviation for the The Product had the average formula methyl radical.All viscosities and refractive indexes (RI) were measured at C. unlessotherwise specified. 25

EXAMPLE 1 Si[(OSi)a.170Si(CH2)a(0C H 1(O O Hq)a.n0OCCH 130.8 g. of

CH =CHCH 0(C H O) (C3H6 M S EXAMPLE 5 was mlxed M11204 ofxy1ene43'2'g'of Employing the procedure of Example 2, 120.3 g. of

Bile F 2( 2 4)2z. C3H OOCCH was re- HMeiSi(OSi)g (OS|i)OSiMezH actedwith 45.5 g. of

Me and 2 g. of 1 percent platinum dispersed on alumina and i Ill/1Bheated at 141 C. for 24 hours. The product was strippedMessxosim'aflosnao51MB,

to a temperature of 200 C. at 1.2 mm. to give a fluid water solublematerial having the following properties: n1, 1.4460; viscosity, 1,368cs. The material had the average general formula in 195.8 g. of xylene.The resulting product had a vis- EXAMPLE 2 5 cosity of 2,175 cs. and arefractive index of 1.4425. The A mixture of 163] of 0 product had theaverage general formula of CH2=CHCH2O(C2H4O)2'1.s(C3H6O)2o.eOCCHa Mei(011mm 0.11.)...(0 031101110 0 c on. 549 g. of w mnio SikOSiMe i.MeSi[(O Si) M0 si p 125 g. of toluene and .2 g. of 1 percent by weightplatinum EXAMPLE 6 as chloroplatinic acid in dimethylphthalate, washeated at The Products of each of the examples was 122 f 24 The productwas then stripped to 0 ployed as a surfactant for the formation ofpolyurethane remove solvent and the residue had a viscosity of 2,655foams 1n the formulatlon- There mlxed cs. and a refractive index of1.4450. This product had the 50 Parts by f of a PolypmPyleneglycolmol of3:000 average formula molecular weight, .7 part by weight of thesurfactant, 1.7 parts by weight water, .28 part by weight dibutyltm d1-laurate, and .04 part by weight triethylamine. These in- MeS i( Si)n.e S(CHi)s0(0iH4 )i1.5( aHi )n.r0 CHila gredients were thoroughly mixed andimmediately there- EXAMPLE 3 after 21 parts of toluene diisocyanate wasadded. The mixture was allowed to foam and in each case an excellentEmploymg the procedure of Example 130's of foam which showed nopneumatic tendencies was obtained. CH4ZCHCH2(OCZH4)354004119)14-4O0CCH3i was 0 Each of the above surfactants waswater dispersible. acted with 42.6 g. of 7 EXAMPLE 7 Me, Me When thefollowing polyalkylene oxides are reacted HMQSKOSDMKOS?)olMeaH with thefollowing siloxanes in accordance with the pro- H cedure of Example 1,the following copolymers are obin 124 g. of xylene at 146.2 C. tained.

9 EXAMPLE 8 48 g. of Me Si(OSiMe- (OSiMeH)-;0SiMe was mixed with 229 g.of

59 g. of isopropanol and 59 g. of toluene. The mixture was heated to 80C. and then 0.5 cc. of a 2 percent by weight solution of platinum inisopropanol was added, the platinum being in the form of chloroplatinicacid. The reaction was complete after about 15 minutes, the mixturehaving become a clear light brown color. The product was stripped to 130C. at mm. of mercury pressure to yield a product having a viscosity of1013 cs., a specific gravity of 1.036, a refractive index of 1.4485 andthe average structural formula The procedure of Example 8 was repeatedexcept that the reactants employed were M638 109.2 OSiMe C2H40) 243C3H6O )253OCCH3 and the product was stripped to 125 C. at 1 mm. ofpressure. The product obtained had a viscosity of 1612 cs., a specificgravity of 1.036, a refractive index of 1.4484 and the averagestructural formula Me MeSi(OSiM8z) 100.21 i)a0 (02 4 24.a( a o )2a.s C cslwO SiMes EXAMPLE 10 The procedure of Example 8 was repeated exceptthat the siloxane reactant employed was Me Si(OSiMe (OSiMeH) OSiMe andthe product was stripped to 133 C. at 13 mm. of pressure, The productobtained had a viscosity of 2061 cs., a specific gravity of 1.037, arefractive index of 1.4484 and the average structural formula Me azhroai w r)a0( 2 4 ).1( a e )25.iOCCHal2o a EXAMPLE 11 The procedure ofExample 8 was repeated except that the siloxane reactant employed was0.6 cc. of the platinum solution was employed, and the product wasstripped to 130 at 8 mm. of pressure. The product obtained had aviscosity of 6269 cs., a specific gravity of 1.037, a refractive indexof 1.4475 and the average structural formula M6 a KOSiMM)sul w ah 2 4)2a.1( 2 a )2o.1O C CHa]aoOSiMea EXAMPLE 12 The products of Examples8-11 were employed as surfactants for the preparation of polyurethanefoams from the following formulation. All parts are on a weight basis.100 parts of a 3500 molecular weight polyether triol, parts ofmonofiuorotrichloromethane, 4 parts of water, 0.15 part oftriethylenediamine, 0.30 part of stannous octoate and 1.4 parts of thesurfactant were thoroughly mixed and then 48.6 parts of toluenediisocyanate added thereto. The mixture was allowed to foam and in eachcase an excellent foam having fine open cells was obtained. These foamsshowed no pneumatic tendencies.

The above foams were also tested for breathability which is a measure ofthe number of open cells in the foam. Breathability" is a numericalmeasure of the amount of air that can be drawn through a specimen of thefoam at a pressure head of 1" of water. The air is drawn through 1"thickness of the foam, the air flow being parallel to the direction offoam rise. The breathability or air flow is reported in cubic feet ofair per minute. The four foams prepared above using the surfactants ofExamples 8-11 had the following breathabilities, respectively, 5.1, 5.4,4.1 and 3.6 cubic feet of air per minute.

That which is claimed is:

1. A method of preparing a polyurethane foam which comprises mixingtogether a polymer selected from the group consisting of hydroxylatedpolyesters and hydroxylated polyethers, a catalyst, a blowing agent, anorganic polyisocyanate and a copolymer selected from the groupconsisting of copolymers having the average structural formulae l R Si[(OSiMe (OSiMeG) OSiMe G] (2) GMe Si(OSiMe (OSiMeG) OSiMe G (3) MeSi(OSiMe (OSiMeG) OSiMe (4) R Si [OSiMe (OSiiMeG) OSiMe in whichformulae R is a hydrocarbon radical free of aliphatic unsaturation andcontains from 1 to 10 carbon atoms,

radicals wherein a R is a radical free of aliphatic unsaturationselected from the group consisting of hydrocarbon and hydrocarbonoxyradicals, the A radical containing a total of less than eleven atoms,

a has an average value of from 0 to 1,

n has an average value of from 6 to 420,

d has an average value of from 0 to 30,

b has an average value of from 1 to 30, and

c has an average value of from 3 to 30,

said copolymers containing at least 13 percent by weight OSiMe unitsbased on the weight of the copolymer, and thereafter allowing themixture to foam.

2. The method of claim 1 wherein the copolymer has the Formula 1.

3. The method of claim 2 wherein d is 0.

4. The method of claim 3 wherein D is a propylene radical and R" iscomposed of ethylene and propylene radicals.

5. The method of claim 4 wherein the copolymer employed has the averageformula 6. The method of claim 3 wherein the copolymer employed has theaverage formula Meg K 2)s.11 2)a( 2 4)2s.i( 4 o)n.24OOCOHa]4 7. Themethod of claim 1 wherein the copolymer has the Formula 2.

8. The method of claim 7 wherein D is a propylene radical and R iscomposed of ethylene and propylene radicals.

Me; Me

10. The method of claim 7 wherein the copolymer employed has the averageformula Meg Me i C1139 0 4 9 )A 2 4 ).4(CH2)sSi(OSi e2) 2a .za[ (CH2)( 2035.40 4 01440 0 C CHaI I)a( 2 4)a5.4( 4119) 14.4 0 C 1 1. The method ofclaim 1 wherein the copolymer has the Formula 3.

12. The method of claim 11. wherein D is a propylene radical and R iscomposed of ethylene and propylene radicals.

13. The method of claim 12 wherein the copolymer employed has theaverage formula I Me;Si(OSiMe AO Si(C Hz) (OCzH4)2r.s(O 01H) 11.1 0 O CCH 1 0 SiMe;

14. The method of claim 12 wherein the copolymer employed has theaverage formula I B18351 (OSiNIGg) 75,3[OS1(C 11:)30 (02H40h0 ,1 (031110(D2510 C CHQ' OSDIBS 15. The method of claim 12 wherein the copolymeremployed has the average formula 17. The method of claim 12 wherein thecopolymer employed has the average formula I Me Si( O SiMe [0 Si( CH1)3O (CgHgOhaJ (OJHBO) as .10 C CH hnO SiMe;

18. In a process for preparing a polyurethane foam, the improvementwhich comprises employing, as the surfactant, a siloxane glycol branchedcopolymer having the average structural formula Me Si (OSiMe (OSiMeGOSiMe wherein Me is a methyl radical,

G is a radical of the structure -D(OR") A wherein D is an alkyleneradical,

R" is composed of ethylene radicals and radicals selected from the groupconsisting of propylene and butylene radicals, the amount of ethyleneradicals relative to the other alkylene radicals being such that theratio of carbon atoms to oxygen atoms in the total OR" blocks rangesfrom 2.3:1 to 2.811,

m has an average value from 25 to 100,

A is a radical selected from the group consisting of the OR, -OOCR and 0ll -0 o o R radicals wherein R is a radical free of aliphaticunsaturation selected from the group consisting of hydrocarbon andhydrocarbonoxy radicals, the A radical containing a total of less thaneleven atoms,

n has an average value of from 6 to 420, and

c has an average value of from 3 to 30.

References Cited UNITED STATES PATENTS 2,834,748 5/1958 Bailey et a1.260-42 2,839,558 6/1958 Kirkpatrick et a1. 260-4482 2,846,458 8/ 1958Haluska 260-4482 3,057,901 10/ 1962 Plueddemann 260-4482 3,194,7737/1965 Hostettler 260-2.5 3,272,762 10/ 1966 Ibbotson et al. 260-25FOREIGN PATENTS 955,916 1/1965 Great Britain.

l,0l5,611 l/l966 Great Britain.

DONALD E. CZAJA, Primary Examiner.

M. B. FEIN, Assistant Examiner.

